This invention relates in general to the field of fluid pumping systems and, more particularly, to a fluid controlled pumping system and method.
Pumping units are used in a variety of applications for compressing, raising, or transferring fluids. For example, pumping units may be used in municipal water and sewage service applications, mining and/or hydrocarbon exploration and production applications, hydraulic motor applications, and consumer product manufacturing applications. Pumping units, such as progressive cavity pumps, centrifugal pumps, and other types of pumping devices, are generally disposed within a fluid and are used to compress or increase the pressure of the fluid, raise the fluid between different elevations, or transfer the fluid between various destinations.
Conventional pumping units, however, suffer several disadvantages. For example, conventional pumping units generally require some form of lubrication to remain operational. For instance, a progressive cavity pump generally includes a rotor disposed within a rubber stator. In operation, a rotational force is imparted to the rotor, thereby producing a corkscrew-like effect between the rotor and the stator to lift the fluid from one elevation to another. In the case of the progressive cavity pump, friction caused by the rotation of the rotor relative to the stator without fluid lubrication oftentimes causes the progressive cavity pump to fail within a relatively short period of time. Generally, the fluid that is being pumped provides the required lubrication. However, variations in the fluid level proximate to an inlet of the pumping unit may result in an absence of fluid lubrication for the pumping unit. Thus, maintaining adequate fluid lubrication at the pumping unit is critical for the performance and longevity of pumping operations. Additionally, in centrifugal pumping applications, an absence of the fluid to be pumped may cause cavitation.
Accordingly, a need has arisen for an improved pumping system that provides increased control of fluid lubrication of the pumping unit. The present invention provides a fluid controlled pumping system and method that addresses shortcomings of prior pumping systems and methods.
According to one embodiment of the present invention, a fluid controlled pumping system includes a pumping unit disposed within a fluid cavity. The pumping unit includes an inlet operable to receive a fluid to be pumped from the fluid cavity. The system also includes a valve slidably coupled to the pumping unit. The valve includes a passage for receiving pump fluid from the pumping unit. The valve is further operable to, in response to a decreasing fluid level within the fluid cavity, move relative to the pumping unit to align a passage of the valve with a port of the pumping unit to recirculate the pumped fluid to the inlet of the pump.
According to another embodiment of the present invention, a method for fluid level controlled pumping includes providing a progressive cavity pump disposed within a fluid cavity. The pump includes a stator/rotor portion for pumping fluid disposed in the fluid cavity. The stator/rotor portion includes an inlet and an outlet. The method also includes providing a valve coupled to the pump. The valve is operable to receive the fluid from the outlet of the stator/rotor portion. The method further includes automatically recirculating the fluid from the outlet to the inlet via the valve in response to a decrease in a fluid level within the fluid cavity.
According to yet another embodiment of the present invention, a fluid level controlled pumping system includes a progressive cavity pump disposed within a fluid cavity. The pump includes a stator/rotor portion for pumping a fluid disposed within the fluid cavity. The stator/rotor portion of the pump includes an inlet and an outlet. The system also includes a valve coupled to the pump and disposed in communication with the outlet. The valve is operable to recirculate the fluid from the outlet to the inlet in response to a decrease in a fluid level in the fluid cavity.
The invention provides several technical advantages. For example, in one embodiment of the present invention, fluid lubrication of the pumping unit is maintained by recirculating the pumped fluid to the inlet of the pumping unit in response to a change in a fluid level within the fluid cavity. For example, according to one embodiment of the present invention, a valve is disposed proximate the pumping unit to recirculate pumped fluid back to the inlet of the pumping unit. Thus, as the fluid level decreases within the fluid cavity, the valve recirculates the pumped fluid to the inlet of the pumping unit to substantially prevent operation of the pumping unit absent fluid lubrication. In one embodiment, the valve may be slidably coupled to the pumping unit, thereby providing movement of the valve relative to the pumping unit in response to changes in the fluid level within the fluid cavity.
Another technical advantage of the present invention includes increased reliability of the pumping unit without necessitating costly user intervention. For example, according to one embodiment of the invention, a valve is slidably coupled to the pumping unit, thereby providing upward and downward movement of the valve in response to variations in a fluid level within a fluid cavity. The valve automatically provides recirculation or the return of the pumped fluid to the inlet of the pumping unit to ensure lubrication of the pumping unit in response to decreasing fluid levels within the fluid cavity.
Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions, and claims.